[Clinical and genetic characteristics of patients with newly diagnosed acute promyelocytic leukemia: a single-center retrospective of 790 cases].

Objective: To retrospectively analyze the data of Chinese patients with newly diagnosed acute promyelocytic leukemia (APL) to preliminarily discuss the clinical and cytogenetic characteristics. Methods: From February 2004 to June 2020, patients with newly diagnosed APL aged ≥ 15 years who were admitted to the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Science & Peking Union Medical College were chosen. Clinical and laboratory features were retrospectively analyzed. Results: A total of 790 cases were included, with a male to female ratio of 1.22. The median age of the patients was 41 (15-76) years. Patients aged between 20 and 59 predominated, with 632 patients (80%) of 790 patients classified as low and intermediate risk and 158 patients (20%) of 790 patients classified as high risk. The white blood cell, platelet, and hemoglobin levels at diagnosis were 2.3 (0.1-176.1) ×10(9)/L, 29.5 (2.0-1220.8) ×10(9)/L, and 89 (15-169) g/L, respectively, and 4.8% of patients were complicated with psoriasis. The long-form type of PML-RARα was most commonly seen in APL, accounting for 58%. Both APTT extension (10.3%) and creatinine>14 mg/L (1%) are rarely seen in patients at diagnosis. Cytogenetics was performed in 715 patients with newly diagnosed APL. t (15;17) with additional chromosomal abnormalities were found in 155 patients, accounting for 21.7%; among which, +8 was most frequently seen. A complex karyotype was found in 64 (9.0%) patients. Next-generation sequencing was performed in 178 patients, and 113 mutated genes were discovered; 75 genes had an incidence rate>1%. FLT3 was the most frequently seen, which accounted for 44.9%, and 20.8% of the 178 patients present with FLT3-ITD. Conclusions: Patients aged 20-59 years are the most common group with newly diagnosed APL. No obvious difference was found in the ratio of males to females. In terms of risk stratification, patients divided into low and intermediate risk predominate. t (15;17) with additional chromosomal abnormalities accounted for 21% of 715 patients, in which +8 was most commonly seen. The long-form subtype was most frequently seen in PML-RARα-positive patients, and FLT3 was most commonly seen in the mutation spectrum of APL.